Method for designing a 20-roller mill intermediate roller profile

Abstract

The application discloses a 20-roller mill intermediate roller shape design method and belongs to the field of plate strip metal calendering. The designed roller shape comprises a flat section and a conical section, and the conical section comprises a transition section and a conical section. The transition section is used for smoothly connecting the conical section and the flat section to ensure the continuity of the roller shape. The method comprises the following steps: designing a conical section roller shape curve function; determining the relationship between the conical section roller shape curve function coefficient and the conical section roller shape parameters; determining the value of the conical section roller shape parameters; determining the value of the conical section roller shape curve function coefficient according to the determined value of the conical section roller shape parameters; and determining the final roller shape according to the determined value of the conical section roller shape curve function coefficient and the value of the conical section roller shape parameters. The application can reduce the risk of high-order wave shape of the plate strip while ensuring the convexity regulation ability of the plate strip, thereby improving the comprehensive control ability of the convexity and high-order wave shape of the plate strip.

Description

Technical Field

[0001] This invention relates to the field of sheet and strip metal rolling technology, and in particular to a method for designing the roll shape of an intermediate roll in a 20-roll mill that takes into account both sheet and strip crown and high-order waviness control. Background Technology

[0002] Conical roll shapes are widely used in cold rolling mills. Reference 1 (Ma Jiaji, Liu Haichao, You Xuechang, et al. A method for controlling edge drop in silicon steel production using Sendzimir Mills [P]. Hebei Province: CN109158429B, 2020-03-20.) designed an intermediate roll shape for a 20-roll mill that can effectively control the edge thickness of silicon steel. Reference 2 (Hara K, Yamada T, Takagi K. Shape Controllability for Quarter Buckles of Strip in 20-high Sendzimir Mills [J]. Transactions of the Iron & Steel Institute of Japan, 1991, 31(6): 607-613.) proposed a design for an intermediate roll shape with a concave roll shape at the location where the high-order wave shape occurs in a 20-roll mill to address the high-order wave shape problem. In reference 3 (Kim JT, Yi JJ, Han SY. Shape control of alloy steel rolled by Sendzimir mill[J]. Journal of Mechanical Science & Technology, 1996, 10(3): 277-285.), Kim proposed a three-cone segment conical scheme to address the difficulty in processing the roll shape scheme proposed by HARA. Industrial tests showed that it could alleviate high-order waviness defects.

[0003] However, multi-conical roll profiles are also difficult to process, requiring smoothing of multiple transition zone cone angles to avoid sharp peaks in inter-roll contact pressure. Therefore, 20-roll rolling in industrial production currently mainly uses single-conical roll profiles. Existing single-conical roll profiles consist of two parts: a straight section and a conical section. For this type of roll profile, when the overlap length between the conical section and the work roll increases, the deflection at the edge of the work roll will be significantly reduced, and the work roll will exhibit a high-order deflection state. This results in excessive local thickness reduction of the strip, which in turn leads to high-order waviness defects. Summary of the Invention

[0004] This invention provides a method for designing the roll shape of an intermediate roll in a 20-roll mill, in order to solve the technical problem that, in the existing method for designing the roll shape of an intermediate roll in a 20-roll mill, when the overlap length between the tapered section and the work roll increases, the deflection of the edge of the work roll will be significantly reduced, and the work roll will exhibit a high-order deflection state, which will lead to excessive local thickness reduction of the strip and thus cause high-order waviness defects.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for designing the roll shape of an intermediate roll in a 20-roll mill, wherein the roll shape of the intermediate roll in the 20-roll mill includes a straight section and a conical region, and the conical region includes a transition section and a conical section; wherein the transition section is used to smoothly connect the conical section and the straight section to ensure the continuity of the roll shape;

[0007] The method for designing the roll shape of an intermediate roll in a 20-roll mill includes:

[0008] Design the roller curve function for the conical region;

[0009] Determine the relationship between the function coefficients of the conical roll profile curve and the roll profile parameters of the conical region;

[0010] Determine the values ​​of the roller profile parameters in the conical zone;

[0011] Based on the determined values ​​of the conical roll shape parameters, and in conjunction with the determined relationship between the conical roll shape curve function coefficients and the conical roll shape parameters, the values ​​of the conical roll shape curve function coefficients are determined.

[0012] Based on the determined values ​​of the tapered roll profile curve function coefficients and tapered roll profile parameters, and in conjunction with the designed tapered roll profile curve function, the profile of the intermediate roll of the 20-roll mill is determined.

[0013] Furthermore, the expression for the tapered region roller curve function is:

[0014]

[0015] Among them, y contour denoted as roll profile; x is the coordinate of an intermediate roll body; a6 and a2 are the coefficients of the roll profile curve function in the conical zone; l1 is the length of the transition section; l2 is the length of the conical section; and k is the taper of the conical section.

[0016] Furthermore, the roller shape parameters of the conical area include: the taper of the conical section, the length of the transition section, the length of the conical section, the height of the transition section, and the overall cone height.

[0017] The relationship between the function coefficients of the conical roll profile curve and the roll profile parameters of the conical region is expressed as:

[0018]

[0019] Where h1 is the height of the transition section; h2 is the overall cone height.

[0020] Further, determining the values ​​of the roller shape parameters in the conical region includes:

[0021] Will Let η be the cone height coefficient of the transition section, and let it be the condition that η must satisfy to ensure that the transition section curve is monotonically increasing; where the condition that η must satisfy is expressed as:

[0022] and

[0023] Determine the values ​​of the transition section length l1 and the tapered section length l2;

[0024] Based on the values ​​of the transition section length l1 and the tapered section length l2, the minimum value that satisfies the condition is taken as the value of η;

[0025] The value of the overall cone height h2 is determined based on the strip convexity control threshold.

[0026] Based on the values ​​of h2 and η, determine the value of the transition section height h1.

[0027] Furthermore, the value range of the transition section length l1 is 100≤l1≤300.

[0028] Furthermore, the length l2 of the conical section is determined based on the maximum overlap length between the conical section and the strip, the length of the work roll, the width of the strip, and the length of an intermediate roll, using the following formula:

[0029]

[0030] Where ξ is the maximum overlap length between the conical region and the plate strip; l w B is the length of the work roll; B is the width of the strip; l f The length of an intermediate roller.

[0031] Furthermore, the value of the transition section length l1 is the same as the value of the tapered section length l2.

[0032] Furthermore, based on the strip convexity control threshold, the value of the overall cone height h2 is determined, including:

[0033] The overall cone height h2 is calculated using numerical methods to ensure that the convexity of the strip reaches the threshold of strip convexity control under the preset overlap length between the tapered segment and the strip.

[0034] The beneficial effects of the technical solution provided by this invention include at least the following:

[0035] The present invention introduces a smooth transition section between the conical and straight sections of a single-conical roll profile. The transition section roll profile has a special geometry that can smoothly connect the conical and straight sections, ensuring the continuity of the roll profile and alleviating the high-order deflection problem caused by the difference in the ability of the conical and straight sections to deflect the work rolls. It can also take into account the strip crown control capability, reduce the risk of high-order waviness, improve rolling stability, further improve the strip yield, thereby improving production efficiency and reducing the strip shape defect rate. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the roll structure of a 20-roll rolling mill;

[0038] Figure 2 This is a schematic diagram of the intermediate roll shape of a 20-roll mill provided in an embodiment of the present invention;

[0039] Figure 3 This is a flowchart of the intermediate roll shape design method for a 20-roll mill provided in an embodiment of the present invention;

[0040] Figure 4 These are the roller shape and single-cone section roller shape diagrams of the present invention;

[0041] Figure 5 This is a comparison diagram of the plastic strain in the rolling direction between the roll shape and the single-cone roll shape of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0043] First, it should be noted that in the embodiments of the present invention, the words "exemplarily," "for example," etc., are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the term "exemplarily" is intended to present the concept in a specific manner. Furthermore, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either one or the other.

[0044] Furthermore, in embodiments of the present invention, sometimes a subscript (such as W1) may be mistakenly written as a non-subscript form (such as W1). Without emphasizing the difference, the meaning they express is the same.

[0045] To address the issue of high-order deflection caused by the difference in the deflection capabilities of the tapered and straight sections on the work rolls, while simultaneously ensuring strip crown control, this embodiment adds a smooth transition section between the tapered and straight sections. Based on this, a roll shape design method for an intermediate roll in a 20-roll mill is provided, which balances strip crown control and high-order waviness control, aiming to reduce the risk of high-order waviness occurrence and ensure strip crown control.

[0046] like Figure 1 As shown, this is a diagram of the roll structure of a 20-roll rolling mill. The method in this embodiment involves designing the roll shape of one of the intermediate rolls, as follows: Figure 2 As shown, the designed roller profile includes a straight section and a conical region, the conical region including a transition section and a conical segment; wherein, the transition section is used to smoothly connect the conical segment and the straight section to ensure the continuity of the roller profile. The overall design idea of ​​this embodiment is as follows: obtain the distribution function of the roller profile curve in the conical region, and determine the roller profile curve coefficients α6, α2 and k to be determined; the roller profile curve coefficients α6, α2 and k can be represented by l1, l2, h1 and h2, and in this embodiment, h1 / h2 is denoted as the transition section cone height coefficient η; according to the smooth transition condition of the roller profile curve, it should be ensured that the slope value of the roller profile curve at the connection point of each segment is the same; the relationship between the cone height coefficient η and l1, l2 is determined according to the positive and negative values ​​of parameter α6 and the monotonically increasing transition section; the maximum overlap length ξ between the conical region and the strip, and the length l of the working roller are used to determine the relationship between the cone height coefficient η and l1, l2. w , strip width B and the length of an intermediate roller l f Determine the values ​​of the transition section length l1 and the tapered section length l2; determine the transition section tapered height coefficient η and the overall tapered height h2 based on the plate and strip convexity control threshold, and then determine the final curve coefficient.

[0047] Based on the above, the execution flow of the method in this embodiment is as follows: Figure 3 As shown, the main steps include:

[0048] S1, Design the roller curve function for the conical region;

[0049] The transition section curve employs sixth-order and second-order polynomials to ensure a smooth transition. The conical section is a linear curve, meaning the ratio of cone height to cone length is constant. Specifically, the function expression for the roller curve in the conical region is:

[0050]

[0051] Among them, y contourdenoted by , x is the roll profile measurement in mm; x is the coordinate of an intermediate roll body in mm; a6 and a2 are the coefficients of the roll profile curve function in the conical zone; l1 is the length of the transition section in mm; l2 is the length of the conical section in mm; and k is the taper of the conical section.

[0052] S2, determine the relationship between the function coefficients of the tapered roll profile curve and the tapered roll profile parameters;

[0053] The roller profile parameters of the conical region include: conical segment taper, transition segment length, conical segment length, transition segment height, and overall conical height. Based on the smooth transition condition of the roller profile curve, the slope values ​​of the roller profile curves at the connection points of each segment should be the same. Therefore, the function coefficients α6 and α2 of the roller profile curve in the conical region and the conical segment taper k can be represented by the following boundary conditions:

[0054]

[0055] From equation (2), the relationship between the function coefficients of the conical roll profile curve and the roll profile parameters of the conical region can be obtained as follows:

[0056]

[0057] Where h1 is the height of the transition section in mm; h2 is the overall cone height in mm.

[0058] S3, determine the values ​​of the roller shape parameters in the conical zone;

[0059] Specifically, in this embodiment, the method for determining the roller shape parameter values ​​for each conical region is as follows:

[0060] S31, let h1 / h2 be denoted as the transition section cone height coefficient η, and determine the condition that η must satisfy to ensure the monotonically increasing transition section curve; among which, to ensure the monotonically increasing transition section curve, the following must be satisfied:

[0061] 6a6x 5 +2a2x≥0 x∈[0,l1] (4)

[0062] When a6 > 0, we can obtain According to the range of values ​​for x, it should satisfy... By representing α6 and α2 in the formula with l1, l2, and η, we can deduce that:

[0063]

[0064] When a6 < 0, we can obtain According to the range of values ​​for x, it should satisfy... By representing α6 and α2 in the formula with l1, l2, and η, we can deduce that:

[0065]

[0066] Therefore, based on the sign of α6 and the monotonically increasing nature of the transition section, the relationship between the transition section cone height coefficient η and l1, l2 can be determined as follows: When and This ensures that the transition curve increases monotonically.

[0067] S32, determine the values ​​of the transition section length l1 and the tapered section length l2;

[0068] The transition section length l1 has a range of 100 ≤ l1 ≤ 300, and is generally the same as l2. w The width of the strip is B mm and the length of an intermediate roller is l. f Confirmed, the calculation formula is as follows:

[0069]

[0070] Specifically, in this embodiment, the maximum overlap length ξ between the conical area and the strip is 148 mm, and the length of the work roll is l. w The thickness is 1414mm, the strip width B is 1250mm, and the length of the intermediate roller is l. f Taking 1580mm, we get l2=230mm. For ease of memorization, we take l1=l2=230mm. It can be determined that when η≥1 / 7 and η≠1 / 3, the transition section curve can be guaranteed to be monotonically increasing.

[0071] S33, determine the value of η based on the values ​​of the transition section length l1 and the tapered section length l2;

[0072] In this embodiment, η is determined based on the relationship between the transition section cone height coefficient η, the transition section length l1, and the cone section length l2, in accordance with the principle of smooth transition and the requirement to meet the range of values ​​for the transition section cone height coefficient η.

[0073] Specifically, in this embodiment, given that l1 = l2 = 230 mm, then η ≥ 1 / 7 and η ≠ 1 / 3, thus determining the minimum transition section cone height coefficient η = 0.15 to retain two decimal places.

[0074] S34, determine the value of the overall cone height h2 based on the strip convexity adjustment threshold;

[0075] In this embodiment, the overall cone height h2 is calculated using a numerical calculation method to ensure that the convexity of the strip reaches the threshold ρ under the overlap length between a certain cone segment and the strip.

[0076] Specifically, in this embodiment, in order to ensure that the convexity control capability of the roller shape of the present invention can reach the convexity control capability of the single conical roller shape (cone length 230mm and taper 0.85%), the convexity control threshold ρ is set to the convexity value of the single conical roller shape (cone length 230mm and taper 0.85%) when the overlap length between the conical section and the strip is 100mm, that is, ρ = -6μm. It can be determined by numerical simulation that the threshold requirement can be met when the overall cone height h2 = 0.725.

[0077] S35. Based on the values ​​of h2 and η, determine the value of the transition section height h1.

[0078] S4. Based on the determined values ​​of the conical roller shape parameters, and combined with the determined relationship between the conical roller shape curve function coefficients and the conical roller shape parameters, determine the values ​​of the conical roller shape curve function coefficients.

[0079] Specifically, in this embodiment, the values ​​of α6, α2, and k are determined based on η, l1, l2, and h2 as follows:

[0080]

[0081] S5. Based on the determined values ​​of the tapered roll profile curve function coefficients and tapered roll profile parameters, and in conjunction with the designed tapered roll profile curve function, determine the profile of the intermediate roll of the 20-roll mill.

[0082] The intermediate roll shape of the 20-roll mill, which takes into account both strip crown and high-order waviness control, provided in this embodiment, was simulated using finite element software. The roll shape of this invention is similar to that of a single-cone section roll. Figure 4 As shown, the plastic strain distribution in the rolling direction of both materials under the condition that the overlap length between the tapered section and the strip is 100 mm and the strip crown reaches the threshold of -6 μm is as follows: Figure 5 As shown, when the strip crown control capability is the same, the local peak value of the plastic strain in the rolling direction of the roll shape of the present invention is only 59.53% of that of the single-cone roll shape under the same strip crown control capability. This indicates that the roll shape of the present invention can effectively reduce the risk of high-order waviness and can also take into account the strip crown control.

[0083] In summary, this embodiment provides a method for designing the roll shape of an intermediate roll in a 20-roll mill. A smooth transition section is introduced between the conical and straight sections of the single-conical roll shape. By designing a suitable roll shape curve form and roll shape parameters for the conical section of the intermediate roll in a 20-roll mill, the method alleviates the high-order deflection problem caused by the difference in the ability of the conical and straight sections to influence the work roll deflection, while also taking into account the strip crown control capability. This can reduce the risk of high-order waviness and improve rolling stability, further increasing the strip yield.

[0084] Furthermore, it should be noted that the present invention can be provided as a method, apparatus, or computer program product. Therefore, embodiments of the present invention can take the form of a completely or partially hardware embodiment, a completely or partially software embodiment, or an embodiment combining software and hardware aspects. Moreover, when implemented in software, embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any usable medium accessible to a computer or a data storage device such as a server or data center containing one or more sets of usable media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive (SSD).

[0085] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0087] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0088] Furthermore, it is understood that in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0089] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0090] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of functional modules / units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs. Additionally, the functional units in the various embodiments of this invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0091] If the method is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0092] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A method for designing the roll shape of an intermediate roll in a 20-roll rolling mill, characterized in that, The intermediate roll profile of the 20-roll mill includes a straight section and a conical section, the conical section including a transition section and a conical section; wherein, the transition section is used to smoothly connect the conical section and the straight section to ensure the continuity of the roll profile; The method for designing the roll shape of an intermediate roll in a 20-roll mill includes: Design the roller curve function for the conical region; Determine the relationship between the function coefficients of the conical roll profile curve and the roll profile parameters of the conical region; Determine the values ​​of the roller profile parameters in the conical zone; Based on the determined values ​​of the conical roll shape parameters, and in conjunction with the determined relationship between the conical roll shape curve function coefficients and the conical roll shape parameters, the values ​​of the conical roll shape curve function coefficients are determined. Based on the determined values ​​of the tapered roll profile curve function coefficients and tapered roll profile parameters, and in conjunction with the designed tapered roll profile curve function, the profile of the intermediate roll of the 20-roll mill is determined. The expression for the tapered region roller curve function is: Among them, y contour denoted by , where x is the roll profile measurement; x is the coordinate of an intermediate roll body; a6 and a2 are the coefficients of the roll profile curve function in the conical region; l1 is the length of the transition section; l2 is the length of the conical section; and k is the taper of the conical section. The roller shape parameters of the conical section include: conical section taper, transition section length, conical section length, transition section height, and overall conical height. The relationship between the function coefficients of the conical roll profile curve and the roll profile parameters of the conical region is expressed as: Where h1 is the height of the transition section; h2 is the overall cone height; The determination of the values ​​of the roller shape parameters in the conical zone includes: Will Let η be the cone height coefficient of the transition section, and let it be the condition that η must satisfy to ensure that the transition section curve is monotonically increasing; where the condition that η must satisfy is expressed as: and Determine the values ​​of the transition section length l1 and the tapered section length l2; Based on the values ​​of the transition section length l1 and the tapered section length l2, the minimum value that satisfies the condition is taken as the value of η; The value of the overall cone height h2 is determined based on the strip convexity control threshold. Based on the values ​​of h2 and η, determine the value of the transition section height h1.

2. The method for designing the roll shape of an intermediate roll in a 20-roll mill as described in claim 1, characterized in that, The value range of the transition section length l1 is 100≤l1≤300.

3. The method for designing the roll shape of an intermediate roll in a 20-roll mill as described in claim 2, characterized in that, The length l2 of the conical section is determined based on the maximum overlap length between the conical section and the strip, the length of the work roll, the width of the strip, and the length of an intermediate roll, using the following formula: Where ξ is the maximum overlap length between the conical region and the plate strip; l w B is the length of the work roll; B is the width of the strip; l f The length of an intermediate roller.

4. The method for designing the roll shape of an intermediate roll in a 20-roll mill as described in claim 3, characterized in that, The value of the transition section length l1 is the same as the value of the tapered section length l2.

5. The method for designing the roll shape of an intermediate roll in a 20-roll mill as described in claim 1, characterized in that, The step of determining the value of the overall cone height h2 based on the strip convexity adjustment threshold includes: The overall cone height h2 is calculated using numerical methods to ensure that the convexity of the strip reaches the threshold of strip convexity control under the preset overlap length between the tapered segment and the strip.

Images